Method of producing ethylene and acetylene



Aug. 13, 1968 c. GLINKA METHOD OF PRODUCING ETHYLENE AND ACETYLENE FiledJan. 25, 1965 2 Sheets-Sheet 1 III. II I11 I;

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gill/Ill VII IIAII Inventor- Carl GZ/nka.

Aug. 13, 1968 c. GLINKA METHOD OF PRODUCING ETHYLENE AND ACETYLENE FiledJan. 25, 1965 2 Sheets-Sheet z Inventor.- Ccu Z 50 0.

b 7 @11 4! fir/hr AA /fi 7 United States Patent ice 7 Claims. of.260679) ABSTRACT 6F THE DISCLOSURE The methods disclosed relate toproducing ethylene and acetylene from high boiling point liquidhydrocarbons, i.e. hydrocarbons having a boiling point between 200 and400. This method consists mainly in conducting the hydrocarbons in theform of a plurality of substantially parallel streaming filaments ofliquid through a stream of inert gas at a temperature above the boilingrange of the hydrocarbons, re-exposing the gaseous hydrocarbons therebyformed to a second stream of inert gas at a temperature high enough tocause ethylene or acetylene to be formed, and then withdrawing theresultant gaseous product through the intervening spaces between thestreaming filaments of liquid hydrocarbons in countercurrent thereto.

This invention relates to a method of producing ethylene and acetylenefrom high boiling liquid hydrocarbons i.e. hydrocarbons having a boilingpoint between 200 and about 400 C. I

According to the invention the heat required for cracking such highboiling hydrocarbons to ethylene and acetylene is introduced by inertgases. Methods of producing ethylene and acetylene from low boilinggaseous and liquid hydrocarbons involving the use of inert gases forintroducing the heat are already known to the art. However, in order toproduce ethylene and acetylene molecules directly from high boilinghydrocarbons special steps must be devised to bring about the muchlarger number of cracking and other reactions required for thedecomposition of the higher molecular stock to the final product and forsupplying the greater quantity of heat that is needed. This heat must bebrought to the treated hydrocarbons by the inert gases within a highertemperature range because the formation temperature of ethylene is inthe neighborhood of about 800 C. and that of acetylene at about 1200 C.The rapid cooling to temperatures below 400 C. of the ethylene andacetylene molecules that are then formed, which is necessary to preventthem from further reacting or decomposing, likewise presents problemsbecause the considerable temperature drop from 1200 C. to under 400 C.of the heat carrier gases and of the products may well adversely affectthe thermal economy of the entire process. Careful consideration mustalso be given to the fact that at temperatures exceeding 1000 C. thegreater proportion of the hydrocarbons is decomposed into carbon andhydrogen and that the carbon thus formed may interfere with the process,fouling the gases as well as the products.

It is therefore the object of the present invention to develop a processin which the reactions occurring in the thermal cracking of high boilinghydrocarbons are so controlled that they will proceed smoothly,economically and without trouble in the manner desired.

According to the invention this is achieved by conducting thehydrocarbons in the form of a plurality of substantially parallelstreaming filaments of liquid through a stream of inert gas at atemperature above the boiling range of said hydrocarbons, by re-exposingthe gaseous hydrocarbons thereby formed to a second stream of inert3,397,251 Patented Aug. 13, 1968 gas at a temperature high enough tocause ethylene or acetylene to be formed and :by then withdrawing theresultant gaseous product through the intervening spaces between saidstreaming filaments of liquid hydrocarbons in countercurrent thereto.

In this method the necessary cooling of the ethylene and/ or acetylenethus formed is achieved by withdrawing the same in countercurrent to thestreaming filaments of cool oil. Owing to evaporation of oil from thesurface of the filaments of liquid that are in contact with the hot gas,the temperature of the oil does not substantially rise and it does notexceed the boiling temperature of the oil. Preferably the temperature ofthe entering oil is maintained at a level of about C. by recycling andcooling the same outside the reactor and by introducing fresh oil toreplace the vaporised oil. The streaming oil filaments are thereforeable to cool the ethylene or acetylene to about 250 C. abruptly within afraction of a second and the ethylene or acetylene molecules are thuspreserved.

In view of the formation temperatures of ethylene and acetylene theinert gases which provide the necessary heat must be sufiiciently hotfor the necessary temperatures to be reached. The temperatures neededfor producing low boiling gaseous hydrocarbons from liquid hydrocarbonsare relatively very much lower. Moreover, since the treating times arevery short it is advisable for the inert gases to have temperaturessubstantially above the boiling range of the liquid hydrocarbons andsubstantially above the formation temperature of the ethylene and/ oracetylene. Generally speaking, the inert gases used for the firstthermal treatment should be at a temperature exceeding 1000 C. and forthe second treatment the gases should have a temperature exceeding 1200C. for the production of ethylene and a temperature above 1500 C. forthe production of acetylene.

Preferably the proposed method may be performed by first conducting astream of inert gas at a temperature exceeding 1000 C. transverselythrough the vertically descending filaments of liquid hydrocarbons andthen into a second stream of inert gas at a temperature exceeding 1200"C., the resultant gas mixture being thereafter reintroduced into thevertically descending filaments of liquid hydrocarbons and withdrawnupwards in countercurrent thereto between the filaments of liquid.Alternatively the method may be performed by withdrawing the gaseoushydrocarbons formed by the action of the first stream of inert gas fromthe process and by reintroducing their low boiling components, afterseparation from the inert gas, into the same stream of inert gas andthen discharging them, together with the products that are formed,upwards between the filaments of streaming liquid in countercurrentthereto.

The invention will now be particularly described by reference to twoillustrative embodiments of apparatus for performing the method. Theseare shown in the accompanying drawings in which FIG. 1 is a longitudinalsection of apparatus for producing ethylene by the method proposed bythe present invention;

FIG. 2 is a section taken on the line IIII in FIG. 1,

FIG. 3 is an illustrative example of apparatus for the production ofacetylene according to the invention, and

FIG. 4 is a section taken on the line IVIV in FIG. 3.

With reference first to FIGS. 1 and 2 a cylindrical upright reactor 1has an enlarged cylindrical head 1b. The lower portion 1a is likewisecylindrically enlarged and lagged with a heat insulating jacket 13. Theenlarged head 1b contains a header tank 2 for the reception of the oilthat is to be processed entering through a pipe 7. The floor 2a of thetank has an annular perforated portion through which the oil, in theform of a large number of separate filaments 3 can descent in free fallthrough the reactor chamber 1 and the upper part of the enlargement 1aat the bottom. The filaments 3 of streaming oil fall into the lower partof the enlargement 1a in which the oil forms a pool communicatingthrough a pipe 5 with a tank 6 containing a fioat 6a which controls thelevel N of the oil in the pool. From tank 6 the oil is forced by a pump8 through a heat exchanger 9 back into the header tank 2. The bottomconed end of the enlarged lower part 10 of the reactor is provided witha cock 10 for draining olf solid deposits. concentrically located insidethe reactor 1 between the two enlarged portions 1a and 1b is a tube 11which extends into the upper part of enlargement 1a, and which definesan annular chamber 12 through which the filaments 3 of streaming oildescend. The annular space inside the enlargement 1a surrounding thepath of the descending oil is divided by a radial refractory ring 4 intotwo parts. The bottom end of the inner tube 11 is protected by arefractory shield 18.

Combustion gases at a temperature of about 1400 C. are generated in afurnace 14 and taken through a duct 15 to a central cylindricaldistributor 16 whence they issue and pass through the filaments 3 ofstreaming oil from the inside roughly in the radial direction P. Some ofthe oil on the surface of the filaments is evaporated and some of theoil vapours thus evolved are converted into gaseous low boilinghydrocarbons by cracking. The evaporation of the oil reduces thetemperature of the combustion gases to about 600 C. and the producedgaseous hydrocarbons mix with gases in that part of the annularenlargement 1a that is situated above the refractory ring 4. A secondstream of combustion gases at a temperature of about 1400 C. is at thesame time tangentially introduced through a duct into this part of theenlargement 1a (cf. FIG. 2). In mixture of this gas into the gas-vapourmixture which has cooled to about 600 C. raises the temperature levelagain to about 800 C. whereby part of the low boiling hydrocarbons inthe combustion gases is converted to ethylene.

The mixture of products, ethylene, hydrocarbons and combustion gasesthus formed leaves through a pipe 17, but first at 19 it isdefiectedinto the path of descent in annular chamber 12 of the filamentsof liquid oil which enters the reactors at a temperature of about 180 C.The gases are thus abruptly cooled to a temperature at which theethylene molecules that have been formed will not further react orcrack. Finally, the products are separated from the combustion gases andisolated.

The relatively small proportion of the recycled oil which evaporatesupon making contact with the hot gases is relaced by the introduction offresh oil which flows into the header tank 2 through pipe 7. Thetemperature of the oil i raised to about 300 C. by the combustion gases.The fresh oil introduced and the cooling effect in the heat exchanger 9maintains an entry temperature of about 180 C.

The first treatment of the oil with the hot combustion gases gives riseto the following products in percent by weight of hydrocarbonsintroduced:

Percent Saturated gaseous hydrocarbons 40 Liquid hydrocarbons 51 Solidresiduum 9 The second treatment with the hot combustion gases produces amixture of the following composition in percent by weight ofhydrocarbons introduced:

The solid residuum comprises the 9% residuum from the first treatmentand a 6% residuum from the second heat treatment.

The plant illustrated in FIGURES 3 and 4 is intended for the productionof acetylene. It differs from that shown in FIGURES 1 and 2 primarily inthat the header tank 22 containing the crude oil that is to be treatedhas a floor 22a with outlet openings distributed over the whole of itsarea and in that the cylindrical reactor chamber 21 is entirely freefrom obstructions, so that the descending filaments 3 of oil fill thewhole of its section. The enlargement 21a at the lower end of thereactor is substantially cone-shaped but comprises a short uppercylindrical portion containing an admission 36 for hot inert gases at atemperature of about 1600" C., such as combustion gases, as well as anadmission 24 for lower boiling gaseous hydrocarbons that have beenpreheated to a temperature of about 200 C. The bottom end of theenlargement 21a is fitted with a trap 30 for the withdrawal of solidsand has an outlet 25 communicating with a tank 26 containing a fioat 26afor keeping the oil pool at a constant level N. From tank 26 the oil canbe pumped back into the header tank 22 by a pump 28. The outlet 37 atthe top of the enlarged head 21b of the reactor 21 is connected to acooler 34 in which the liquid hydrocarbons precipitate and from whichacetylene, ethylene and very low boiling hydrocarbons, namely thoseboiling under 0, are withdrawn overhead at 35. Hydrocarbon fractionsboiling between 0 and 150 C. are withdrawn at 38 and 39 and taken into acontainer 29 whence they are blown by a pump 31 into the upper part ofenlargement 21a through admission 24. FIG. 4 shows that the admissionsin the enlargement 21a are tangential. Hydrocarbons boiling above C.leave the cooler 34 at the bottom 40 and How into the sump of thereactor.

The inert gases which are blown into the bottom enlargement 21a at atemperature of 1600 C. through admission 36 flow in the direction ofarrow P1 in a descending spiralling path and penetrate into the interiorof the streaming shower of filaments 23. They therefore make contactwith the descending filaments of oil 23. Part of the oil vapour thusproduced is converted into lower boiling hydrocarbons which are thenwithdrawn upwards in countercurrent to the streaming filaments of oiland taken to the cooler 34 through pipe 37. From the cooler hydrocarbonsboiling between 0 and C. enter tank 29 and after their temperature hasbeen raised to 200 C. they are blown by pump 31 tangentially in thedirection of arrow P2 into the upper part of enlargement 21a. Theytherefore mix with the hot 1600 C. gases flowing as indicated by arrowP1 and are thus now partially converted to acetylene and ethylene. Themixture of hot inert gases, acetylene, ethylene and hydrocarbons ascendsbetween the filaments of liquid oil in countercurrent thereto and iscooled to about 250 C. before returning to the cooler 34 through pipe 37The acetylene and ethylene that have been formed, the inert gases, andhighly volatile hydrocarbons leave together through pipe 35, whereas theremaining hydrocarbons pass through the cycle again.

The temperature of the oil in the header tank 22 is maintained at atemperature of about 180 C. by the supply of fresh oil through pipe 27or by a cooler not specially shown in the drawing, which may correspondto cooler 9 in FIG. 1. During their descent these hydrocarbons thereforeremain liquid and form a pool in the sump at the bottom of theenlargement 21a. During its descent the temperature of the oil may riseto near boiling point. The temperature of the gas which is blown inthrough admission 36 at 1600 C. may drop a few hundred degrees to say1200 C. in chamber 21a and when the gas and the gaseous products thathave formed have entered the path of the oil streams 23 theirtemperature abruptly falls to about 400 C., a temperature which may befurther reduced to about 250 C. as the gases pass upwards between thefilaments of streaming oil.

What I claim is:

1. A method of producing ethylene or acetylene from liquid hydrocarobnsboiling between 200 and 400 (3., comprising conducting said hydrocarbonsin the form of a plurality of substantially parallel streaming filamentsof liquid through a stream of inert gas at a temperature above theboiling range of said hydrocarbons, re-exposing the gaseous hydrocarbonsthereby formed to a second stream of inert gas at a temperature highenough to cause ethylene or acetylene to be formed, and then withdrawingthe resultant gaseous product through the intervening spaces betweensaid streaming filaments of liquid hydrocarbons in countercurrentthereto.

2. The method claimed in claim 1, wherein the first stream of inert gasis at a temperature exceeding 1000 C. and the second stream of inert gasis at a temperature above 1200 C.

3. The method claimed in claim 1, wherein the first stream of inert gashas a temperature exceeding 1000 C. and the second stream of inert gashas a temperature above 1500 C.

4. The method claimed in claim 1, comprising conducting a stream ofinert gas at a temperature exceeding 1000 C. transversely through thevertically descending filaments of liquid hydrocarbons and then into astream of inert gas at a temperature above 1200 C., the gas mixturebeing finally taken upwards between the vertically descending filamentsof streaming hydrocarbons in countercurrent thereto.

5. The method claimed in claim 1, comprising withdrawing thehydrocarbons formed in the first stream of hot inert gas, separating thelighter boiling components from the inert gas, returning them into thestream of hot inert gas and finally withdrawing them together with theproducts that form in countercurrent upwards between the verticallydescending streaming filaments of liquid hydrocarbons.

6. The method claimed in claim 1, comprising conducting the hydrocarbonsthat have passed through the stream of hot inert gas, together with thesolids formed therein, to apparatus for treating fuels containing waterand ash, and then recycling them for further treatment after they havebeen cooled to at least 200 C. and the solids have been removedtherefrom.

7. The method claimed in claim 5, wherein the inert gas has atemperature of about 1600" C.

References Cited UNITED STATES PATENTS 2,113,536 4/1938 Grebe et a1.260-679 2,921,100 1/1960 Pettyjohn 260679 2,934,410 4/1960 Smith 1606793,005,857 10/1961 Steinhoferetal 260679 DELBERT E. GANTZ, PrimaryExaminer.

I. D. MYERS, Assistant Examiner.

